The reconstruction of the breast following ablative surgery has become an increasingly frequent surgical procedure. The development and use of silicone-gel and saline-filled silastic implants have contributed to the increasing frequency of this procedure. Thickening and contracture of the fibrous capsule surrounding the silastic implant, however, remains a major post-surgical problem. Animal studies, as well as histologic evaluation of human capsule segments, have revealed the nature of this fibroproliferative response. Leakage or "bleeding" of silicone gel from silastic breast implants appears to be a major cause of this inflammatory response which ultimately results in a constrictive fibrosis surrounding silicone-gel implants. The use of less reactive filling substances may offer the possibility for the prevention of capsular contracture. As such, we propose a feasibility study of balloon-type implants with a highly biocompatible filling substance. It is anticipated that a breast prosthesis of this type will minimize thickening and contracture of the fibrous capsule surrounding the prosthesis.